Once the toner is transferred from the drum to the paper, residual electric charges (and toner particles) remain on the drum. A corona wire is used to erase this charge so that it does not affect the next printing. This wire extends across the drum beyond the point where the paper was processed. A current passing through the wire, creates a 'corona' of electric charge. As the drum rotates past this effect, it erases the electrostatic charge. Residual toner is then removed from the surface by a soft-bristle brush which spans the drum. Occasionally, two corona wires are used to insure that all residual charge is erased before the next printing.
